Without limiting the scope of the invention, its background is described in connection with composite materials.
Synthesis of particle containing composite materials is a very active area of technology. This activity reflects the fact that these composites represent an opportunity to create novel new materials. Potential applications, recently noted or patented for such new materials, include optoelectronics, coatings, sealants, caulks, adhesives, and biofunctional materials, as but a few of the examples in this area.
A variety of innovative techniques have been employed to prepare these hybrid inorganic-organic materials. However, the preparation processes employed are liquid based and generally involve simple physical mixing of the inorganic or metallic particles with the liquid reagents. Typically, if preliminary coating of the particles is attempted, it involves simple physical adsorption of an organic compound, usually the monomer, unto the inorganic moiety, followed by subsequent polymerization of the monomer to create the final composite polymeric assembly.
In contrast with the above procedures, the present invention involves covalent attachment of the particles to the polymeric organic matrix. Briefly, a plasma deposition step is initially employed to deposit reactive functional groups, strongly grafted, on the surface of a solid substrate, followed by immersion of the coated substrate in a solution during which time target molecules react with the functional surface groups introduced during the plasma process, as taught in U.S. Pat. No. 5,876,753, issued to Timmons, et al., for molecular tailoring of surfaces. In this way, the targeted molecules are attached to the surface during this second step. The two-step process is of general use because the nature of the plasma introduced surface groups and the nature of the solute molecules can be varied. Additionally, it is possible to provide exact control of the surface density of reactive groups introduced during the plasma process and thus the concentration of targeted molecules coupled to the solid surfaces. The second step chemical derivatization reactions can be carried out using aqueous or non-aqueous solutions at variable temperatures.